ISO WHITE 



flies, and dragon-flies), that were just emerged out of their 

 aurelia state. I then no longer wondered that they should be 

 so willing to stoop for a prey that afforded them such plentiful 

 and succulent nourishment. 



They bring out their young about the middle or latter end of 

 July ; but as these never become perchers, nor, that ever I could 

 discern, are fed on the wing by their dams, the coming forth 

 of the young is not so notorious as in the other species. 



On the 3Oth of last June, I untiled the eaves of a house 

 where many pairs build, and found in each nest only two 

 squab, naked pulli ; on the 8th July I repeated the same 

 inquiry, and found that they had made very little progress 

 towards a fledged state, but were still naked and helpless. 

 From whence we may conclude that birds whose way of life 

 keeps them perpetually on the wing would not be able to quit 

 their nest till the end of the month. Swallows and martins, 

 that have numerous families, are continually feeding them 

 every two or three minutes ; while swifts, that have but two 

 young to maintain, are much at their leisure and do not attend 

 on their nest for hours together. 



Sometimes they pursue and strike at hawks that come in 

 their way ; but not with that vehemence and fury that swal- 

 lows express on the same occasion. They are out all day long 

 in wet days, feeding about, and disregarding still rain : from 

 whence two things may be gathered : first, that many insects 

 abide high in the air, even in rain ; and next, that the feath- 

 ers of these birds must be well preened to resist so much wet. 

 Windy weather, and particularly windy weather with heavy 

 showers, they dislike ; and on such days withdraw, and are 

 scarce ever seen. 



There is a circumstance respecting the color of swifts, which 

 seems not to be unworthy of our attention. When they arrive 

 in the spring, they are all over of a glossy, dark soot-color, 

 except their chins, which are white ; but, by being all day long 

 in the sun and air, they become quite weather-beaten and 

 bleached before they depart, and yet they return glossy again 

 in the spring. Now, if they pursue the sun into lower lati- 

 tudes, as some suppose, in order to enjoy a perpetual summer, 

 why do they not return bleached ? Do they not rather per- 



